Vehicles having two, three, or more wheels are generally known. Within this genus of vehicles, certain types of tilting three-wheeled vehicles are known, such as the STREAM™ and CANOPY™ scooter of Honda and the ELLISSE™ scooter of Protos, which is described in WO 98/43872. The CANOPY™ scooter, for example, has two rear wheels supported by a track hinged on the frame of the scooter to pivot about the longitudinal axis thereof. The axis of the rear wheels does not tilt when the scooter takes curves, but remains parallel to the ground.
Three-wheeled vehicles are also known having one driving rear wheel and two steering front wheels. For example, European Patent Application No. EP1180476 B1 describes a laterally tilting three-wheeled vehicle having two steering front wheels. This vehicle has improved roadholding capabilities to keep the center of gravity between the wheels to reduce or prevent rollover.
Electric vehicles are known with on-board charging system as described in U.S. Pat. No. 6,326,765, with a composite frame as described in U.S. Published Application No. 2005/0092538, and with a regenerative braking system as described in U.S. Pat. No. 6,724,165.
There remains, however, a need to assist the rider in keeping a vehicle upright or keeping it from tipping over when moving at slow speeds or when stopped, especially for small and light-weight riders.